Process for improving the resistance to soiling of poly(beta-lactone) fibers

ABSTRACT

A process for improving the resistance to soiling, i.e., reducing the soilability, of polypivalolactone fibers is described which comprises (1) applying to said fibers a polymeric compound comprising polymerized oxyalkylene units and polymerized beta-lactone units and (2) heating the treated fibers to a temperature of at least 140* C.

United States Patent Moseley et al. Mar. 7, 1972 [54] PROCESS FOR IMPROVING THE [56] References Cited RESISTANCE TO SOILING OF POLY(BETA-LACTONE) FIBERS UNTED STATES PATENTS 2,917,410 12/1959 Vitalis ..Z60/78.3 [721 Mmccm shafsbmy 2,962,524 11/1960 Hostettler et al. ....260/78 3 gaff m? g' gr j g' 3,268,487 8/1966 KlOOIWijk .260/78 3 bale fax; a 3,312,753 4/1967 Bailey et a1. 260/78 3 Ridgeyx'td Rkemead Engemel 3,477,998 11/1969 Nakahara a: al.... ....260/78.3 Green, Egham, Surrey, a of England 3,536,516 10/1970 OOSlelhOf 6t 81. ..260/78.3 [22] Filed: Apr. 27, 1970 Primary Examiner-William D. Martin I Assistant Examiner-Raymond M. Speer [211 32352 Attorney-Joseph W. Brown and Norris E. Faringer [30] Foreign Application Priority Data [57] ABSTRACT y 9, 1969 Great Bfiiain 3,7 9 A process for improving the resistance to soiling, i.e., reducing the soilability, of polypivalolactone fibers is described which [52] U-S-CI. ..117/138-8 A, 1 17/139.5 A, 117/161 K, comprises (1) applying to said fibers a polymeric compound 260/783 comprising polymerized oxyalkylene units and polymerized 1 ll- CI- betaJaetone units and heating the treated to a em. [58] Field 61 Search ..117/138.8 A, 138.8 F, 139.5 A, pmmre least 117/161 K, 161 UB, 161 UC;260/78.3

9 Claims, No Drawings PROCESS FOR IMPROVING THE RESISTANCE TO SOILING OF POLY(BETA-LACTONE) FIBERS BACKGROUND AND SUMMARY OF THE INVENTION Polylactone fibers, particularly polypivalolactone fibers, have many interesting and useful properties but their nonhydrophilic character makes them, to some extent, prone to easy soiling. Once soiled, the fibers cannot be easily and effectively washed with conventional washing techniques and domestic detergent formulations. Hence there is a need to improve the resistance of the fibers to soiling and to improve the washability of soiled fibers.

In accordance with the present invention such improvements may be obtained by applying to the fibers a polymeric compound comprising polymerized oxyalkylene units and polymerized beta-lactone units and heating the fibers to a temperature of at least 140 C.

Also disclosed are polylactone fibers having improved soilrelease performance.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention relates to a process for improving the resistance of polypivalolactone fibers to soiling. The term fibers whenever used in this specification, including the appended claims, includes any type of fiber or fibrous article such as continuous monofilaments, staple fibers, yams, threads, woven or nonwoven fabrics.

POLY(BETA-LACTONE)FIBERS Polylactone fibers which can be improved by the present treating process are the polymers, including homopolymers and copolymers, obtained by polymerizing beta-lactones, particularly the alpha,alpha-dialltyl-beta-propiolactones wherein the alkyl groups contain from one to four carbon atoms, including those compounds in which the two alkyl groups and the alpha-carbon atom of the lactone ring are combined to form one cyclic structure, such as, for example, 2-oxa-4-spiro[ 3.6]decanone-l. Suitable examples include alpha,alphadirnethyl-beta-propiolactone, alpha-methyl-alpha-ethyl-betapropiolactone, a1pha-methyl-a1pha-isopropyl-beta-propiolactone, alpha-ethyl-alpha-tert-butyl-propiolactone, alpha,alphadiisopropyl-propiolactone, etc. The most preferred alpha,alpha-dialkyl-beta-propiolactone is alpha,alphadimethyl-beta-propiolactone.

The poly(beta-lactones) may be prepared by any conventional means, usually in the presence of a suitable catalyst, (see U.S. Pat. No. 3,021,309, U.S. Pat. No. 3,268,486, British Pat. No. 766,347, French Pat. No. 1,231,163 or Belgian Pat. No. 649,828).

Suitable catalysts which may be used in polymerizing the beta-lactones include the primary, secondary or tertiary amines such as trimethylamine, triethylamine, tri(betahydroxyethyl)amine, tripropylamine, triisopropylamine, methyldiethylamine, tri-n-butylamine, diethyl-n-butylamine, dimethylhexylamine, triphenylamine, diethylamine, di-npropylamine, diisopropylamine, dibutylamine, monobutylamine, monophenylamine, triethylenediamine, hexamethylenetetraamine, and the like. Other catalysts include quaternary ammonium compounds and especially the tetraalkylammonium halides or hydroxides where the alkyl groups contain from one to about four carbon atoms such as tetraethylammonium bromide, tetrapropylammonium bromide, ethyltriisopropylammonium chloride, tetraethylammonium hydroxide, etc. These catalysts are disclosed in copending U.S. application Ser. No. 388,662, filed Aug. 10, 1964 and now U.S. Pat. No. 3,268,487.

Another group of very suitable polymerization catalysts are the arsines, stibines and phosphines as well as the addition products thereof. Suitable catalysts of this type are those disclosed in copending U.S. application Ser. No. 363,992, filed Apr. 30, 1964 and now U.S. Pat. No. 3,268,486, the description thereof which is incorporated herein by reference. Especially preferred catalysts of this type are the tertiary phosphines and the quaternary phosphonium compounds such as trimethylphosphine-,.- triethylphosphine, tri( betachloroethyl)phosphine, tripropylphosphine, triisopropylphosphine, tri-n-butylphosphine, triisobutylphosphine, dimethylhexylphosphine, diethyl-n-pentylphosphine, and diisopropyln-butylphosphine, triphenylphosphine, tribenzylphosphine and tritolylphosphine tetrabutylphosphonium bromide, triphenylbutylphosphonium bromide, tetraethylphosphonium hydroxide and ethyltriisopropylphosphonium bromide.

The terms polymerizing, polymerization, polymer and monomer, whenever used in this specification, should be interpreted as covering also copolymerizing, copolymerization, copolymer and comonomer. By copolymerization is meant that the beta-lactories are polymerized together among themselves or with other compounds that can be polymerized. Examples of compounds that can be copolymerized with betalactones are, for example, epoxy compounds such as ethylene oxide, propylene oxide, epichlorohydrin, and glycidyl ethers and esters, and the like.

Suitable catalysts for preparing lactone polymers having a very high-molecular weight include the organic compounds of an element of Group Va of the Periodic system.

In general, the catalyst may be employed in widely varying concentrations,-for example, in concentrations of 0.0001 to 10 percent by weight, calculated on the monomer. Ordinarily, however, concentrations of 0.001 to 1 percent by weight are utilized.

The resulting beta-lactone polymers may be fabricated into monofilaments, threads, woven material, etc., by any conventional method such as melt spinning, with or without drawdown, quenching and/or annealing.

Since the preparation of polymers of the bcta-lactones and their subsequent fabrication into fibers form no part of the present invention, no further discussion on them is appropriate.

POLYMERIC TREATING COMPOUNDS As noted hcreinbefore, the polymeric compounds which are suitable comprise polyoxyalkylene units and polypivalolactone units.

In the said polymeric compounds, the polymerized oxyalkylene units are present as polyoxyalkylene groups such as polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene groups or copolymers thereof with polyoxyethylene groups being preferred. These groups may be considered as being derived from the corresponding polyoxyalkylene glycols by omitting one or both of the terminal hydrogen atoms. The molecular weight of these groups may suitably vary from to 5,000, preferably from 600 to 3,000.

The polymerized beta-lactone units are present as linear polyester groups obtained by homo or copolymerization of beta-lactones, such as beta-propiolactone or alpha,alpha-dialkyl substituted beta-propiolactones in which the alkyl groups comprise from one to four carbon atoms. Examples of the latter lactones are pivalolactone, which is the preferred lac tone, alpha,alpha-diethyl propiolactone or alpha-methylalpha-propyl propiolactone. The molecular weight of the polyester groups suitably varies from 350 to 10,000, preferably from 400 to 2,500,

In general, the number of polyester and polyoxyalkylene groups present in the molecules of the polymeric compounds is not critical, apart from the fact that there should be at least one of each of these groups. Hence it is possible to combine one polyester group with say two or four polyoxyalkylene groups or the reverse. Likewise, the weight ratio of these groups may vary between rather wide limits. For example, ratios of 50:1 or 1:50 are not excluded although ratios from 5:1 to 1:5 are preferred.

It is possible to prepare the polymeric compounds by various alternative methods. Thus, for example, suitable compounds may be obtained by esterification of polypivalolactone or another beta-lactone polyester having a carboxyl group as terminating group, with a polyoxyalkylene glycol or polyoxalkylene glycol monoalkyl ether or ester or by reacting such a polyester with an alkylene oxide under polymerizing conditions. The lactone polyesters having a carboxyl group as terminating group may have been prepared by using any of the known polymerization initiators such as amines, phosphines and phosphoniurn halides.

Alternatively, the lactone may be polymerized in the presence of a polyoxyalkylene glycol or monoalkyl ether or ester thereof in the absence of an alkaline catalyst, preferably in the absence of any catalyst. In the latter polymerization reactions, the hydroxyl group or groups of the said polyoxyalkylene compounds are believed to function as polymerization initiators, the polymerization reaction then proceeding via beta-alkyl-oxygen fission of the lactone. Thus, in the case of monohydric polyoxyalkylene compounds, such as polyoxyalkylene monoalkyl ethers or esters, the reaction may be represented as:

HE... use.) o solasifl +5 Art- OH I

in which R is a divalent polyoxyalkylene radical and m and n correspond with the appropriate molecular weight of the polyester groups. Obviously, such polymerization reactions may be followed by esterification reactions in which one or more of the terminal carboxyl groups react with unconverted or subsequently added polyoxyalkylene glycol. Likewise, one or more of the terminal carboxyl groups may be neutralized or esterified with monomeric alcohols or glycols.

Similar reactions may also be employed to prepare the polypivalolactone or other beta-lactone. polyesters with terminating carboxyl groups referred to hereinabove. Suitable polymerization initiators for these reactions are monomeric mono, di and polyhydric hydroxyl compounds such as ethanol, isopropanol, ethylene glycol or the ethyl and butylether thereof, di, tri or tetra ethylene or propylene glycols and monoalkyl ethers or esters thereof, dihydroxy and trihydroxy propane, l,2,3-tris( hydroxy methyl)propane, 1 ,2,2- tris(hydroxy methyl)propane, 1,3-dihydroxy-2,2,bis(hydroxy methyl)propane, 1,2,3,4,5,6-hexahydroxy n-hexane, and sucrose. The preparation of pivalactone polymers employing nonphenolic hydroxy compounds in the absence of alkaline catalysts is described in copending US. Pat. application Ser. No. 845,093, filed July 25, 1969 and now abandoned. The products of such polymerization reactions which generally have a relatively low-molecular weight, may then be esterified by reaction with polyoxyalkylene compounds to provide for the required polymeric compound comprising both polymerized oxyalkylene and polymerized beta-lactone units.

As will be clear the polyoxyalkylene groups and the linear polyestengroups in all the polymeric compounds prepared as discussed hereinbefore are directly linked together in such a way that the polyoxyalkylene groups are either linked to the alkyl ends or to the carbonyloxy ends of the linear polyester 'groups. The linkage between the different groups does not necessarily have to be a direct one. it is also allowed to link groups together via suitable bridging compounds, for example,

hydroxy carboxylic acids, such as hydroxypivalic acid or 4- hydroxy butanoic acid or amino acids.

The polymeric compounds may be applied to the fiber by' any suitable method, for example, as solutions or dispersions in an inert liquid medium, such as water or other aqueous media. Organic media which do not affect the physical and chemical properties of the fibers may be employed as well. For reasons of economy the amount of the compounds to be applied to the fiber will as a rule be kept as low as possible. Adequate improvement of the fibers is generally obtained when applying the compounds in amounts of from 0.3 to 15 percent by weight, preferably from 0.7 to 7.5 percent by weight, based on the weight of the fiber. After the removal of the inert liquid media, whenever employed, the fibers are heated at a temperature of at least C. This heating is effected to ensure a permanent attachment of the compounds to the fibers. The term permanent" should be interpreted herein as referring to an attachment which is substantially resistant towards the repeated washing, scouring, dry-cleaning and similar laundering treatments to which the fibers may be subjected in practice.

The time period and the temperatures to be adopted for the heat treatment are not critical as long as thetreatment results in effecting the said permanent attachment of the compounds to the fibers. Of course the temperature may not exceed the melting temperature of the fibers which generally is from 240 to 244 C. Preferred heating temperatures are from 180' to 220 C., and preferred time periods are from 0.5 to 5 minutes. High-heating temperatures may be combined with short heating periods, whilst the reverse likewise holds.

The process in accordance with the invention is illustrated by the following examples. Unless otherwise specified, parts are given by weight.

Examples 1, 11 and 111 illustrate the preparation of the present treating polymers. Examples 1V and V illustrate the performance of the treating polymers prepared in Examples l, ll and Ill.

EXAMPLE 1 e... l. L

wherein m+ng 16.

Subsequently, the polymer (9.2 millimole) was reacted with a polyethylene glycol having a molecular weight of 1,500 (9.2 millimole) using 75 ml. of xylene as a refluxing diluent and 0.3 gram of p-toluene sulphonic acid as esterification catalyst. After stirring with K CO (2 gram) the xylene solution was concentrated to 70 ml. and then diluted with 500 ml. diethyl ether to precipitate 17.3 gram (60 percent weight yield) of a white solid (Product A). Analysis of this solid product indicated that the carboxyl terminated polymer had been esterified with the polyethylene glycol to form a mixture of esters in which the ratio of polyoxyalkylene to polyester moie ties was 1:] and 1:2.

EXAMPLE 1] 9.2 millimole of the pivalolactone polymer with a molecular weight of 1,640, described in Example 1, was reacted with 13.8 millimole of a polyethylene glycol with a molecular weight of 1,500 by heating under reflux in xylene for 12 hours using ptoluene sulphonic acid as a catalyst. After stirring with K CO the solution was filtered and xylene was removed from the filtrate to precipitate a 20.7 gram (90 percent weight yield) of a pale brown solid (Product B).

EXAMPLE 111 9.2 millimole of the pivalolactone polymer with a molecular weight of 1,640 described in Example I was reacted with 9.2 millimole of a polyethylene glycol with a molecular weight of 800 in the manner described in Example 11. Working-up was also effected as described in Example [1. A white solid was obtained in a yield of 76 percent weight 16.4 gram, Product C).

EXAMPLE lV Products A, B and C were applied to fabrics of plain woven polypivalolactone filaments by padding with aqueous dispersions of those products. The fabrics were then dried in an oven at 60 C. and then heated for sec. at 200 C. Products A and B were applied to the fabrics in an amount of 2.5 percent weight (based on fibers), the amount of Product C was 1.0 percent weight.

Samples of control fabrics and treated fabrics were washed in an automatic washing machine at 60 C. for 10 minutes, using a household low-lather detergent formulation. The concentration of the detergent in the washing liquid was 0.5 percent weight (as solution). This washing was repeated nine times, giving 10 washings in all.

Thereafter all samples were subjected to a sequence of five soiling-washing cycles using as the soiling liquid a dispersion of 0.03 g. of airborne dirt, 0.02 g. of greasy soil and 0.003 g. of a nonionic detergent in 500 milliliter water. The washing liquid used in the sequence was water containing 0.2 percent weight of the same household low-lather (low-sudsing) detergent mentioned above.

The performance of the Products A, B and C was expressed as a value S which is determined according to the equation 1 S=log% in which R and R are reflectance readings recorded from a Gardner reflectometer when testing the unheated control sample and the samples which had been subjected to the sequence of five washing-soiling cycles. The lower the values of S, the better is Similar samples as described in Example IV were tested on stain release performance of products A to C. The samples were stained with a cherry red lipstick (L), dirty motor oil (0) and red pepper sauce (P). The stains were allowed to set at room temperature overnight. Then the samples were twice washed and dried in the automatic washing machine, again using low-lather detergent. The performance of the products was determined by visual means and expressed in a relative scale in which a figure five relates to complete removal and one relates to virtually no removal of the stains.

Restaining and testing after 10 further washing treatments gave very much the same results, thus showing that the products not only have a good stain release performance but are also markedly wash-fast. The results are tabulated in Table 11.

TABLE II After 2 After 12 washes washes After 2 After 12 washes Washes 1 After 2 After 12 washes washes I Restained after 10 washes.

Treatment We claim as our invention:

1. A process for improving the resistance of poly(beta-lactone) fibers to soiling which comprises (1) applying to said fibers from about 0.3 to 15 percent by weight of said fibers a polymeric compound comprising polymerized oxyalkylene units having a molecular weight of from 150 to 5,000 and polymerized beta-lactone units comprising linear polyester groups having a molecular weight from 350 to 10,000, said weight ratio of polyoxyalkylene units to polyester groups being from 1:50 to 50:1 and (2) heating the treated fibers to a temperature of at least C.

2. A process as in claim 1 wherein the beta-lactone is an alpha, alpha-dialkyl-beta-propiolactone wherein each alkyl group contains one to four carbon atoms.

3. A process as in claim 2 wherein the beta-lactone is alpha,alpha-dimethyl-beta-propiolactone.

4. A process as in claim 1 wherein the polymerized oxyalkylene units are present as polyoxyethylene groups.

5. A process as in claim 4 wherein the polyoxyethylene groups have a molecular weight of from 600 to 3,000.

6. A process as in claim 1 wherein the polymerized beta-lactone units are linear polyester groups having a molecular weight from 400 to 2,500.

7. A process as in claim 1 wherein the weight ratio of polyoxyalkylene units to polyester groups is from 1:5 to 5:1.

8. A process as in claim 1 wherein the polymeric compound is applied in amounts from about 0.7 to 7.5 percent by weight.

9. A poly(beta-lactone) fiber treated by the process of claim 

2. A process as in claim 1 wherein the beta-lactone is an alpha, alpha-dialkyl-beta-propiolactone wherein each alkyl group contains one to four carbon atoms.
 3. A process as in claim 2 wherein the beta-lactone is alpha, alpha-dimethyl-beta-propiolactone.
 4. A process as in claim 1 wherein the polymerized oxyalkylene units are present as polyoxyethylene groups.
 5. A process as in claim 4 wherein the polyoxyethylene groups have a molecular weight of from 600 to 3,000.
 6. A process as in claim 1 wherein the polymerized beta-lactone units are linear polyester groups having a molecular weight from 400 to 2,500.
 7. A process as in claim 1 wherein the weight ratio of polyoxyalkylene units to polyester groups is from 1:5 to 5:1.
 8. A process as in claim 1 wherein the polymeric compound is applied in amounts from about 0.7 to 7.5 percent by weight.
 9. A poly(beta-lactone) fiber treated by the process of claim
 1. 